| A | B |
| audi/aud | hear |
| anti | opposite/against |
| audible | able to be heard |
| audience | a group of people who watch or listen to something |
| audio | sound heard on a recording or broadcast |
| auditorium | a large room or building where people gather to hear a speech or watch a performance |
| antidote | a substance that stops the harmful effects of a poison; something that corrects or improves the bad effects of something |
| antisocial | violent or harmful to people; not friendly to other people. |
| antipathy | a strong feeling of dislike |
| antiseptic | a substance that prevents infection in a wound by killing bacteria |
| antibody | a substance produced by the body to fight disease |